There’s a lot of speculation about Stephen Colbert stepping into the CBS late-night slot, and what he’ll be like with his “real” persona.

Fans expecting to see “the real Stephen Colbert” when he starts his late-night talk show Tuesday (Sept. 8) might be surprised at what they get.

If so, they won’t be alone, because someone else is also expecting to be surprised: Stephen Colbert.

“Honest to God, it’s an act of discovery for me, too,” Colbert told TV writers in August. “All I know is that it’s the same creative team, so I’m just as excited about the jokes.”

When Colbert moves into David Letterman’s old 11:35 p.m. weeknight slot, he has a pair of elephants waiting for him.

The first is the freshly departed ghost of Letterman, who gave the show a singular brand over 22 years and who some viewers now regard as the last of the old-school late-night lions, more in the host mold of Johnny Carson than the entertainment-driven Jimmy Fallon or Jimmy Kimmel.

Stephen Colbert, future host of “The Late Show,” takes a selfie with David Letterman.

(Jeffrey R. Staab)

The second is Colbert’s own shadow, from the stylized conservative character he created on “The Daily Show” and later on “The Colbert Report.”

That character made him famous and in all likelihood landed him the “Late Show” gig. It also left such an indelible imprint on its large cult of fans that they have spent the last few months wondering what Colbert will be like once he’s stepped out of that skin and into his “real” persona.

“It feels a little bit like therapy,” Colbert mused recently. “‘Who is the real Stephen Colbert? Why did you wear a mask? What were you running from? Let it out. It’s a late-night comedy show. Cry.’

“I don’t think anybody would have watched that old show if they didn’t know who I was — because that guy was a tool, and we did our best from the very beginning to peek around the mask.

“Not to get too erudite, but Oscar Wilde said something along the lines of ‘Do you want to see somebody's real face? Give them a mask.’”

Colbert is amusing himself by flirting with psychobabble here. But Michael Harrison, publisher of the trade magazine Talkers, says he’s making a critical point.

“One of the standard pieces of advice everyone hears in this business is ‘Be yourself,’” says Harrison. “But it’s not as cut-and-dried as it might seem. It’s not that simple to say about Colbert, ‘Now he’s going to reinvent himself.’

“Everybody who’s a performer has shtick to some extent. So I don’t think there's that much of a delineation between your character and who you ‘really are.’”

“The Colbert Report” is gone, so Stephen Colbert won’t be able to rely on the conservative-doofus shtick any more.

(Scott Gries/AP)

Colbert, perhaps to the surprise of some fans, agrees.

“I was able to piggyback on the back of that character and be extremely intimate with the audience because I had the excuse that I didn’t mean it,” he said. “But I’m here to tell you I meant a lot of it. I even agreed with my character sometimes.

“My hope is that when you see me on the new show, you’ll go, ‘Oh, wow. A lot of that was him the whole time.’ But I won’t know how much of it is until I do it.”

One definite and positive change as he morphs from the old Colbert character to the new Actual Colbert, he says, is that interviews will become less stressful.

“All I really want from a guest is somebody who has something to say so I can play with them,” he said. “We have some common topic to be talking about. My character was actively ignorant about them. [That was] one of the reasons why I most wanted to drop the character. . . . I felt I had done everything I could with him other than have my honest interest in my guest.

“Now I feel more freed up. Now I don’t have to hold back. I had to put everything through (my brain) to render what my character would think about what the person just said, but still have my intention behind it.

Stephen Colbert pops in to take a selfie with Jimmy Fallon on the latter’s “Tonight Show” debut.

(Lloyd Bishop/AP)

“Now I can just talk.”

Streamlining the thought process is good, Harrison agrees.

“Quite often performers themselves don’t know who they are,” Harrison says - and ironically, “if you become too self-aware, it can come across to the audience as inauthenticity.”

Musician Jon Batiste is joining Stephen Colbert’s new late night program as the show’s bandleader.

(Betsy Newman/CBS)

Harrison also suggests that Colbert’s new show is arriving on a late-night television landscape that has changed dramatically in a relatively short time.

“We’re in the post-Carson, post-Leno, post-Letterman era,” he says. “Most of the guys that are there now are absolute performers — very polished, very skilled, very practiced, very thought-out.

“I don't think any of it is as spontaneous as the audience might think, or as it was in earlier days.”

Colbert says he strives for spontaneous because that sets up his favorite kind of comedy, which in turn is why interviews will be a critical component of whatever mix the show settles into.

“I got into comedy through improvisation,” he said, “and when you’re interviewing people, you don’t know what’s going to happen. That’s much closer to how I learned my craft.”

So now, he says, he can theoretically talk to guests on his TV show as he would talk to a guest in his living room when no cameras were rolling.

The question is not much whether that’s “real,” suggests Harrison, as how it will come across on a TV screen — and that’s almost impossible to predict or define.

The marquee on the exterior of the Ed Sullivan Theater with new signage saying “The Late Show with Stephen Colbert” to reflect the new host taking over the show at 1697 Broadway.

(Andrew Schwartz/For New York Daily News)

“It used to be that all acting was a performance,” Harrison says. “Then along came Marlon Brando and ‘method acting,’ and the person on the screen suddenly was talking like the person in the next seat. If we hadn’t had that change, all actors would still sound like Katharine Hepburn.

“What we’re really talking about here is authenticity. We use the term ‘real,’ but you can be authentic and not be ‘real.’

“Authenticity is such an elusive commodity for spoken-word performers. It’s a very abstract blend of different parts of the human psyche. You can’t define it in words.”

“Every show is really a reflection of the guy behind the desk,” Colbert says. “I don’t know where it’s going. I won’t know until I’m doing it. I have my own hopes for the kind of show that I want to do, but I won’t know until I’m on my wave. All I can feel right now is the swell behind me, and I’m paddling as fast as I can.”